Before computer processing can begin, all system data must be converted for
input to the main programs. The hardware data, schematics, and wire lists must
be replaced with computer codes. The software data can be read in directly from
a magnetic tape.

The system hardware data are input to the computer using a computer terminal,
where interactive programs allow error checking as the data are entered. The
encoded data represent every hardware component in the system and the
connectivity among the components. In converting software data, the language
being used must be defined so that the sneak analysis programs can interpret the
instructions. Based on its function and syntax, each instruction is classified
into one of 16 groups.